Setting: the same one as this question and this question; TL;DR, life is common throughout the Universe, it just tends to blow itself up before it figures out FTL travel and upgrades to Kardashev 2, which turns out to be very rare; hence, there are a few civilizations alive in every galaxy at a given time, but there is only one civilization that had the exact right course of events to actually come up with FTL. They're fine interacting with other species and would like to build cities or space stations that can house multiple different species at the same time, as is a staple of science fiction: Captain Legallydistinct never has any problem going down to an alien planet's surface and meeting up with the locals at a party, and the humans suggest at the Interstellar Conferences that we should work towards being able to have safe interspecies parties just like in Galaxy Journey.

Here I will enumerate some of the species that I'm dealing with (using pseudonyms, because I haven't exactly come up with English transliterations for their names yet):

  • Humans. We are quite versatile and can live in areas that get as cold as 0 ºC or as hot as 20 ºC on a regular basis (for this question's purposes, I will operate under the assumption that that temperature range is "comfortable" for humans who have endured the unimaginable hardships of space travel). We also prefer 1 g, but there is some thought that we could survive in 1.5 or even 2 gs of gravity for short periods of time, and I'm sure nobody would be offended to have to spend time in 0.2 g and be able to fly around with cardboard wings (again, I will assume that that range is roughly comfortable, so humans' gravity range is 0.2 to 2 g). We can’t go too low for too long, though - our bones begin to atrophy and our heart begins to shut down.
  • Dragons: the one species who has figured out how to build an energy-efficient and actually-functional warp drive, and the one who brought all the other species together. They have radically-different chemistry based on silicon, making them less fleshy than rocky, but they're still just as motile and intelligent (if not far more intelligent) as humans. They come from a world where the average temperature is around -100 ºC and the gravity is around 0.15 g, and without constant life support, they can't stand temperatures above -50 °C without getting heatstroke and promptly dying, but they can get as cold as -200 °C by slowing down their metabolisms and going into a sort of stasis until it warms up again. They can deal with surface gravities up to about 0.5 g before the square-cube law kicks in and they can’t hold themselves up anymore. They drink a mix of silane chemicals, and breathe methane; their chemistry doesn’t like oxygen or water but neither are toxic to a dragon.
  • Elves: another carbon-based species born on a moderately Earth-like planet with gravity around 0.7 g and temps around -70 °C (I said Earth-like, not Earth-identical), the elves are a thick-furred bipedal species that have learned to use electricity generated by their photovoltaic fur to power much of their musculature instead of biochemical energy. They drink water and breath oxygen like humans, but can’t deal with temperatures hotter than 0 °C - their thick fur can be used as a high-surface-area radiator to keep them from passing out in very high temperatures, but at a certain point they overheat and, not being able to sweat, suffer heatstroke and die. They can deal with a human’s gravity of 1 g easily, and their resilient bones can let them survive in 0 g for as long as necessary; their circulatory system, which has to constantly pump blood to the radiator-like furred skin to keep them from overheating even under ambient temperatures, has to keep running all the time, even in zero g.
  • Dwarves: carbon-based lifeforms that hail from a super-Earth orbiting a much brighter star, leading to surface temperatures upwards of 80 °C and gravities of around 2.5 g. They can put up with temperatures as high as 120 °C, as much life on their planet has evolved to due because its eccentricity carries it much closer to the sun during the summer, resulting in large temperature fluctuations over the course of a year. They can also withstand temperatures as cold as 40 °C, but below that point, their biochemistry starts to shut down and they suffer rapid decomposition - not exactly good. They can deal with high and low gravity as well, being a hardy species.

Obviously, there are some issues here. Some species would freeze to death in Death Valley, while others would die of heatstroke in Antarctica, while the dragons (who have established FTL travel and are pretty much the only way to get all four species together until an enterprising human steals their tech) would be crushed under high gravity as they suffocate.

Humans, elves, and dwarves have all figured out advanced computing, so they can just render holograms of each other in their ships and have the super-mega-genius equivalent of a video call, but the dragons are embarrassed to admit that, on account of their hyperintelligence, they never bothered to develop computers powerful enough to render holograms since all the calculations a computer would do they can do in their heads, and there aren’t cats on their world and there is therefore no impetus to create high-quality GPUs to stream videos of them. As such, the dragons not wanting to just wait around in silence having taxied everyone else within comms range, we need another solution.

So: what’s a convenient, casual solution that these four species could implement to allow them to have casual in-person conversations with each other without promptly overheating, freezing, being crushed, and/or asphyxiating? Putting on spacesuits and exoskeletons to withstand different gravities, atmospheres, and temperatures doesn’t exactly count, since that’s not what any of these species would consider to be “casual”. The result I’m aiming for is an explanation as to how a dragon, a dwarf, a human, and an elf can all walk into the same room without spacesuits on and not instantly be killed by something (since that happens fairly often in my world).

  • 3
    $\begingroup$ Check your human liveable temperature range. -20 to +40 is pretty comfortable with normal off the shelf clothing and adequate food and water. $\endgroup$
    – g s
    Commented May 1 at 19:44
  • 1
    $\begingroup$ Logic check, have you considered how elves are able to drink water when they can't tolerate its temperature? Water freezes at 0C, and that's the elves high end tolerance. $\endgroup$
    – Karen
    Commented May 2 at 12:04
  • $\begingroup$ Your premise is inherently broken. It can't work. And we didn't create GPUs to stream anything, they arose out of the gaming market. We were streaming cats long before the first commercially-available GPUs. $\endgroup$
    – Corey
    Commented May 3 at 2:44
  • $\begingroup$ do the dragons really need to see the others for a casual conversation to take place? Are they as visual as humans? Wouldn't some other mode of perception be as meaningful for them as vision is for humans? $\endgroup$
    – Charon ME
    Commented May 3 at 7:10
  • 1
    $\begingroup$ Let the dragons buy GPUs from us...? $\endgroup$ Commented May 3 at 17:35

7 Answers 7


These species simply cannot "walk into the same room" - there is no atmosphere that could fill the room which would be amenable to all. As such, we require separate environments.

This would be accomplished the same way that we have separated environments of different temperature and pressure throughout history - with a wall. If you want to look at who or what is on the other side of the wall, you can even put in a window. Everyone can have their own atmosphere at whatever temperature they want, and still be able to see and communicate with others.

The only thing that might need to be constant for all the environments is the amount of gravity, but since everyone can handle low G's, we simply need to put the divided meeting room in a low-G environment.

  • 19
    $\begingroup$ I'd note that I have a special room in my own house which has at times simultaneously a walled >200 degree environment, a walled <-20 degree environment, and 20-30 degree environment, and I feel casual in my kitchen. $\endgroup$
    – g s
    Commented May 1 at 19:37

They can't.

You've put it right there in your question: some of these species cannot survive at the temperatures, pressures, and gravities that others require. That's the end of it.

There's no way to make the environments they require coexist within the same room. If there's a temperature or pressure differential that strong, it will very quickly undifferentiate itself unless you stop it, but the mechanism to do so will be at least as bulky and obtrusive as a spacesuit. For instance, you could keep a dwarf strapped into a chair in a tank that's heated to 80°, but the insulation needed to keep it from melting the human next to it would be pretty formidable, so much so that they're not really in the same room any more. They're in two rooms that happen to be next to one another with a lot of sapphire glass in between.

Ultimately, in the kinds of sci-fi you're talking about, where the captain and the new aliens sit around a table having a pleasant discussion fifteen minutes after discovering each other's species exist, aliens tend to all be pretty human-like, and come from planets that are pretty Earth-like. That's one option that's available to you. Dwarves can be from a planet that's a little hotter and higher gravity, but not so much that they can't tolerate Earth. They just grumble about it.

Or, you can use some kind of technological intervention, whether that's videoconferencing, or environment suits, or some kind of robotic or organic proxy.

But you can't have a room that somehow has all of those divergent environments in it at the same time with everyone in shirtsleeves, without the kind of technology that makes all of those options downright primitive in comparison.


Dragon technology: forcefields.

Handy thing technology. The forcefields can be modulated to prevent gas exchange or allow it, to reduce gas flow or prevent it altogether.

They can also be made sound-permeable.

This enables close-ish personal contact in a controlled space.

Alternatively, the dragons can wear personal shield generators carrying around their atmosphere and heat, neatly contained for a certain duration before the power/gas supply runs low.

Same with the dwarves, a gift of the dragon-race - just ensure no-one gets too close for too long, it'd be like standing next to a hot oven.

For exchange of objects, brief openings can be modulated in the fields, not long enough to do any dammage.

  • $\begingroup$ the same can arguably be achieved with soundwaves. VERY precise soundwave emitters can create "sound forcefields" to keep hot and cool air from mixing, locally change pressure, and most importantly, allow people to amplify and send their voice to communicate across the room without standing too close. In fact, it could even be used to send TOUCH as a message, since concentrated sound can be used to push physical objects. So imagine a room full of people with slightly shimmering air bubbles around them, which can talk to anyone in the room or mute anybody else, touch without touching etc. $\endgroup$ Commented May 6 at 9:57
  • $\begingroup$ Nice idea @GoingDurden . Why not write that up as a potential solution of the OP... $\endgroup$ Commented May 6 at 10:18

The problem isn't the gravity, it's the temperature

Firstly assuming that antigravity technology doesn't exist in your setting. The room of the encounter could be in a space station with 0g or 0.5g (by artificial gravity), therefore all of the species would be in a comfortable gravity.

(Note: for humans here today 2g is too extreme, we can't live more than a week in 2g and it would be uncomfortable, the max tolerable is 1.5g)

As for the temperature, all the species need a different one to be comfortable (I assume that in a reunion of the 4 species, all of them would prefer to talk at a comfortable temperature), so the room where they talk could be separate in 4 areas one for each species and the temperature that they prefer.


Sounds like you've set up an impossible problem and then ask for a solution. If we start with the assumption that A can only survive at temperatures from -100 to -80, and B can only survive at temperatures from 50 to 100, at what temperature can both survive? The answer is clearly "none". You've defined it as impossible.

So the only options are:

  1. Some sort of space suits. You rule this out, but why? Why not suppose that in this high tech society, they can make space suits that are reasonably comfortable and non-awkward.

  2. They communicate electronically, by Zoom or some future equivalent. But you ruled that out too. (Seems like you deliberately set out to make the problem unsolvable.)

  3. They don't occupy the same room.

3.1. Relatively low tech: They have adjoining rooms at different temperatures, atmospheres, etc, with a window between them.

3.2. They send robot avatars to a common place and talk through the robot avatars.

  1. Don't make their required environments so radically different. Say that one species can live at -10 to +30 C, and another can live at -50 to +10 C, etc, so there's an area of overlap where one feels hot and the other feels cold but they can both survive.

  2. You could have some metaphysical solution, like they use astral projection to send their spirits to the meeting room. That might well take the story in a very different direction, though.

** Follow on thought **

If the ranges aren't TOO far apart, the creatures might be able to put up with discomfort. Like one could say that human beings require temperatures of around 0 C to 30 C to function. But a human could SURVIVE at -20 or +50. Especially if all they have to do at the extreme temperatures, pressures, etc, is sit and talk. And now I'm thinking, What are the limits of what you could "get used to"? Like I spent most of my life in Ohio and Michigan, where temperatures tend to be cool to cold. -20 was not uncommon in Michigan. But now I live in the Philippines, where it is routinely high 20s to low 30s. And I'm getting used to it. I used to think 28 was unbearably hot. Now I think it's comfortable to maybe a bit cool. The thermometer on my desk as I type this says 29.3 and I feel quite comfortable. Could I get used to 35? Probably. 40? I'd guess not. I don't know if any studies have been done on this.


This can arguably be achieved with soundwaves. VERY precise soundwave emitters can create "sound forcefields" to keep hot and cool air from mixing, locally change pressure, and most importantly, allow people to amplify and send their voice to communicate across the room without standing too close. In fact, it could even be used to send TOUCH as a message, since concentrated sound can be used to push physical objects, including bodies.

So imagine a room full of people with slightly shimmering air bubbles around them, which can talk to anyone in the room or mute anybody else, touch without touching etc.


Yes, no problem.


0.3g - 0.4g is tolerable to all four species.


The atmosphere in the room is a mix methane and oxygen. Methane is inert and is only dangerous to humans (and presumably by extension to elves and dwarves) when it replaces oxygen, and you've stated that oxygen is not toxic to your methane breather.


This must be achieved with microclimates. In principle you have the radiator on as well as the aircon - but a bit more extreme...

Something like this: enter image description here

Small print: NO SMOKING - seriously. ...and any naked flames used to power the furnace must be atmospherically decoupled from the gas mix being circulated.


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